X-Git-Url: http://www.git.cypherpunks.ru/?a=blobdiff_plain;f=doc%2Ftransport.texi;h=4b8413b23e470b0cb58543ecaa4c92c89d572731;hb=bea62b33bb6f217dcb05b7b6be0e6327abf60fc3;hp=f5ca87e1f0576df4af79d0df51595a16caf4c64f;hpb=d9008bcb18fd32450934ba2803ca1634486e9855;p=govpn.git diff --git a/doc/transport.texi b/doc/transport.texi index f5ca87e..4b8413b 100644 --- a/doc/transport.texi +++ b/doc/transport.texi @@ -25,15 +25,16 @@ TAG || ENCRYPTED || NONCE --> PACKET @end verbatim @code{SERIAL} is message's serial number. Odds are reserved for -client(->server) messages, evens for server(->client) messages. +client (to server) messages, evens for server (to client) messages. @code{PRP} is XTEA block cipher algorithm used here as PRP (pseudo random permutation function) to obfuscate @code{SERIAL}. Plaintext @code{SERIAL} state is kept in peers internal state, but encrypted before transmission. -XTEA's encryption key is the first 128-bit of Salsa20's output with -established common key and zero nonce (message nonces start from 1). +XTEA's encryption key @code{PRP_KEY} is the first 128-bit of Salsa20's +output with established common key and zero nonce (message nonces start +from 1). @verbatim PRP_KEY = 128bit(ENCRYPT(KEY, 0)) @@ -45,8 +46,7 @@ Salsa20's output is ignored and only remaining is XORed with ther data, encrypting it. @code{DATA} is padded with @code{PAD} (0x80 byte). Optional @code{ZEROS} -may follow, to fillup packet with the junk to conceal pyload packet -length. +may follow, to fill up packet to conceal payload packet length. @code{AUTH} is Poly1305 authentication function. First 256 bits of Salsa20's output are used as a one-time key for @code{AUTH}.